\documentclass{minimal}
\usepackage{pstricks-add, multido}
\parindent=0pt

% run through latex -> dvips -> ps2pdf14(!) and view 
% with Acrobat >= 5.0

\begin{document}

\psset{fillstyle=solid,linestyle=none}
\multido{\rA=0.25+0.25}{4}{
  \begin{pspicture}(-3.25,-3.25)(3.25,3.25)
    \pscircle[fillcolor=green,opacity=\rA](2;135){2cm}
    \pscircle[fillcolor=red,opacity=\rA](2;45){2cm}
    \pscircle[fillcolor=blue,opacity=\rA](1;-90){2cm}
  \end{pspicture}\\
}

\begin{verbatim}
\psset{fillstyle=solid,linestyle=none}
\multido{\rA=0.25+0.25}{4}{
  \begin{pspicture}(-3.25,-3.25)(3.25,3.25)
    \pscircle[fillcolor=green,opacity=\rA](2;135){2cm}
    \pscircle[fillcolor=red,opacity=\rA](2;45){2cm}
    \pscircle[fillcolor=blue,opacity=\rA](1;-90){2cm}
  \end{pspicture}\\
}
\end{verbatim}

\end{document}








